Looking at the endless abundance of high-level languages, one might think that assembler has long died. But this is not so. Suppose you write a library and want to collect all the strings in one object file. Even using the lowest level of all the higher levels - C, nothing will work. All C compilers are the same in this respect. I have an answer why this is happening. But for now, I will refrain from discussing.
The simplest program and assembler for it.
#define STR1 ";string_1\r\n"
#define STR2 ";string_2\r\n"
#define STR3 ";string_3\r\n"
#define STR4 ";string_4\r\n"
#define STR5 ";string_5\r\n"
#define STR6 ";string_6\r\n"
extern int printf();
void _start (void){
printf(STR1);
printf(STR2);
printf(STR5);
}
section code
[global _start]
_start:
; Line 8: void _start (void){
L_4:
; Line 9: printf(STR1);
push dword L_1
call printf
pop ecx
; Line 10: printf(STR2);
push dword L_2
call printf
pop ecx
; Line 11: printf(STR5);
push dword L_3
call printf
pop ecx
; Line 12: }
L_5:
ret
section data
section code
section data
section string
L_3:
db ";string_5"
db 0dh
db 0ah
db 00h
L_2:
db ";string_2"
db 0dh
db 0ah
db 00h
L_1:
db ";string_1"
db 0dh
db 0ah
db 00h
section const
section code
[extern printf]
We have 6 strings, and only 3 are in the object file. Let's cut the program down to the can’t.
#define STR1 ";string_1\r\n"
#define STR2 ";string_2\r\n"
#define STR3 ";string_3\r\n"
#define STR4 ";string_4\r\n"
#define STR5 ";string_5\r\n"
#define STR6 ";string_6\r\n"
section code
section data
section code
section data
section const
The object file is full zero. And now we take the assembler and by the hands, hands
SECTION .data
SECTION .data
STR1:
db ";string_1", 0dh, 0ah, 00h
STR2:
db ";string_2", 0dh, 0ah, 00h
STR3:
db ";string_3", 0dh, 0ah, 00h
STR4:
db ";string_4", 0dh, 0ah, 00h
STR5:
db ";string_5", 0dh, 0ah, 00h
STR6:
db ";string_6", 0dh, 0ah, 00h
;.....
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